<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
      li{
          list-style: none;
          width: 40px;
          height: 40px;
          background-color: pink ;
          background-image: url('./images/cpinfo_icons.gif');
          
      }
    </style>
</head>

<body>
    <ul>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>
    <script>
       var li=document.querySelectorAll('li')
       for(var i=0;i<li.length;i++){
           var index=i*40;
           li[i].style.backgroundPosition='0 -'+index+'px'
       }
    </script>
</body>
</html>